372 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



believed Gisle'n to be right in his decision that Comatula purpurea is only a form or 

 variety of C. pectinata, but that the 3 specimens in the present collection throw 

 little light on the question. 



COMATULA TENUICIRRA A. H. Clark 



Plate 39, Figure 110 



Comatula tenuicirra A. H. CLARK, Proc. Biol. Soc. Washington, vol. 25, 1912, p. 20 (description; 

 Siboga station 320); A. H. CLAKK, Unstalked Crinoids of the Siboga Exped., 1918, p. vin 

 (discovery by the Siboga and its significance); p. 276 (listed); pi. 15, figs. 19, 20. 



Comatula (Comatula) tenuicirra A. H. CLARK, Unstalked Crinoids of the Siboga Exped., 1918, p. 27 

 (in key; range); p. 29 (references; detailed description; station 320). 



Diagnostic features. The cirri are confined to the interradial angles of the centro- 

 dorsal, where they occur singly or in pairs as in C. purpurea. The longest cirrus 

 segments are twice as long as broad instead of being little, if at all, longer than 

 broad as in C. purpurea. 



Description. The centrodorsal is as in C. purpurea. 



The cirri are V-IX, 14-15, from 13 to 15 mm. in length, occurring singly or in 

 pairs in the interradial angles. The first segment is short, the second is nearly as 

 long as broad, the third is from one-third to one-half again as long as broad, and 

 the fourth and fifth are twice as long as the median width. The following segments 

 gradually become slightly shorter so that the third before the antepenultimate is 

 about one-third again as long as broad, the next is slightly longer, the antepenultimate 

 is half again as long as broad, and the penultimate is very slightly longer than broad. 

 The cirri are very slender, and are of the same type as the slender form of cirri found 

 in C. purpurea and in C. pectinata. 



The 10 arms are from 80 to 125 mm. in length in the larger specimens; they 

 resemble the arms in the slender-armed form of C. purpurea. 



The second and third segments of the proximal pinnules are very strongly 

 carinate. 



Notes. Except for the longer and more slender cirri this form exactly resembles 

 the slender armed variety of Comatula purpurea. 



Of the additional specimens examined, one has the arms 80 mm. long and the 

 cirri V. Another has the arms 55 mm. long and the cirri VII. A third has the 

 arms 50 mm. long and the cirri IV. Two others have the arms 40 mm. and 35 mm. 

 long and the cirri V. The remaining two are small. The cirri of these small examples 

 are extremely delicate. The color is yellow brown. Some of the specimens have a 

 stripe of dull purple on either side of the median dorsal line, and one has in addition 

 a spot of purple on each of the pinnule segments. 



Localities. Siboga station 320; Java Sea, north of the eastern end of Madoera 

 (lat. 6 05' 00" S., long. 114 07' 00" E.); 82 meters; fine gray mud; February 23, 

 1900 [A. H. Clark, 1912, 1918] (8, U.S.N.M., E. 401; Amsterdam Mus.). Pi". 39, 

 fig. 110. 



Siboga station 318; northeast of Madoera (lat. 6 36' 30" S., long. 114 55' 30" 

 E.); 88 meters; fine yellowish gray mud; February 22, 1900 (5, U.S.N.M., E. 470). 



Remarks. This species has not been found since the original specimens were 

 collected by the Dutch steamer Siboga in 1900. 



